How I can get medical for Oman

Hi myself Shiv Dyal from Himachal Pradesh in India. I have got Oman work visa as a Concrete Batching Plant Operator. Now they said to me that take medical by gamca and then came Oman now. But I don't know about gamca. Please tell me that how I can get medical for that. Please tell me nearst gamca medical in Himachal where I take medical. Please help me.